Concrete reinforcing element and method of making a concrete reinforcement

Abstract

Tensioning elements for construction purposes comprising reinforcing rod for prestressing concrete can be fabricated from steel of the following composition: 0.7 to 1.0% by weight Mn 0.7 to 2.2% by weight Cr 0.3 to 0.6% by weight Mo 0.5 to 2.2% by weight Ni up to 0.45% by weight C (preferably at least 0.1% by weight C.) balance iron and unavoidable steel impurities which is subjected to austenitization, oil quenching and optional tempering to a tensile strength of 1400 to 2000 N/mm 2 and an elongation to break in excess of 7% and preferably about 10% and is welded to a terminal element of the same composition but having a tensile strength substantially 10-20% less than that of the rod, and then incorporated into a concrete structure.

We claim: 
     
       1. A process for making a concrete reinforcement, comprising the steps of: forming a reinforcing element having a composition consisting essentially of: 0.7 to 1.0% by weight manganese   0.7 to 2.2% by weight chromium,   0.3 to 0.6% by weight molybdenum,   0.5 to 2.2% by weight nickel,   up to 0.45 by weight carbon and   balance iron and unavoidable steel impurities; and     drawing or rolling said reinforcing element,   heating said element initially to an austenitization temperature,   quenching said element; and   tempering said reinforcing element to a tensile strength of substantially 1400 N/mm 2  to 2000 N/mm 2  and an elongation to break of at least 10%;   forming a terminal member with a threaded end and an end to be welded having said composition,   heat treating said member to a tensile strength substantially 10 to 20% less than that of said reinforcing element,   welding said reinforcing element to the end to be welded of said terminal member for forming the concrete reinforcement; and   incorporating said element in a concrete structure.   
     
     
       2. The process defined in claim 1 wherein said reinforcing element is formed as being a ribbed rod. 
     
     
       3. The process defined in claim 2 wherein said reinforcing element is formed as a wire. 
     
     
       4. The process defined in claim 3 wherein said wire is formed with a diameter of at least 1 mm.